That’s way below the estimated 80% share that Walmart, for example, pays for labour.

So if you accept Posner’s theory that data is labour, then companies who make money from marketing your data are essentially getting labour for free. And it’s not only your personal data they exploit. It’s also the many hours of labour it takes to create social media content in the first place – and the hours we spend viewing and responding to the content made by others.

Working out what your data is worth

Despite the personal data industry generating some US$200 billion in revenue every year, data brokers give little, if any, money back to the providers of this asset.

Admittedly, valuing personal data isn’t easy.

Let’s take Facebook, for example. If we divide its revenue (US$40.7 billion in 2017) by the number of monthly active users (2.196 billion), then each user is worth US$18.53 on average.

You could think of this figure as the amount that your Facebook data is worth.

Of course, this is a very simplistic calculation. Even without using your data to target you with ads, Facebook’s size means it could still make money from advertising – just like any other media outlet. But it’s the targeting that helps Facebook dominate the digital advertising market.

If you combine your Facebook data with the rest of your digital footprint, some estimate that an average US consumer could make up to US$240 per year. This amount could be much higher if you include other valuable data, such as your purchase history, location, and financial information.

So our data could make us money.

Some companies already pay for it

Market research companies have been paying people for their data for decades.

So if some companies are already paying for personal data, why isn’t everyone paying for it?

There are two main reasons for this.

First, our data are dispersed, fragmented and inaccessible. People who use ad blockers, “do not track” tools, and high privacy settings erode the quality of data that can be gathered about them. So each company with which they interact has only a small portion of their data, which can lead to errors in targeted marketing.

The holy grail of data integrity is when your data comes directly from you. This means it’s 100% accurate, comprehensive, and handed over with explicit consent.

Second, unlike other possessions, it’s hard for individuals to trade data. If data can’t be easily sold at the owner’s will, it’s difficult to extract value from it.